A few questions on configuring more than 2 Subs with 2 Main Channels (ie..2.3 or 2.4...etc)

justbob

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Hello,

I've been using Audiolense for a few years now with great success and have v6.7 installed currently. My setup up to this point has been pretty basic with a 2 Channel configuration with 2 Subs running in Stereo. I've been considering strongly adding either one or two more Subs to the current setup but before going down that path I would like to better understand the "Speaker Setup" of how this would work with Audiolense.

A basic rundown of my current gear is as follows:

Merging Hapi 8ch DA Converter
Pass Labs Mono Blocks
Magico S3 Towers
2 x Rythmik E15HP2 - SE Subs
Roon for Playback/Convolution/DSP Vol Control

Below is what my current Audiolense Speaker Setup Tabs look like for the setup above:

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I've been reading thru the various Forum posts here and seeing some impressive and complex configurations being used with Audiolense so I have no doubt what I want to do is achievable but before making any additional equipment purchases I would like to have a good understanding of what my future state Speaker Setup options are when adding a 3rd or 4th additional Sub to the equation. Thus far I have found that using Subs in a Stereo configuration seem to sound better to these ears having tried a Mono Sub configuration in the past but I'm not married to such a configuration if things need to change in order to make this work.

Below is mock future state Speaker Setup I have been playing with inside Audiolense for a 4 Stereo Sub configration but am not sure if this will do what I want or not so any help folks here can provide would be appreciated:

4 Stereo Sub Configuration

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With the future state configuration posted above my plan would be to have two Subs on the Left side of the Room and two Subs on the Right side of the room to maintain a typical Stereo layout. As best I can tell with the mock up configuration shown the two new Subs would receive the same signal feed that the existing two Stereo Subs receive but am not 100% sure?

With the new setup I am unable to configure a Low Pass x-over value on the x-over Tab but my assumption is that they will just inherit the Bass Routing value set on the first Speakers Tab since the Channel ID's are the same for both pairs of Subs?

So thus far I have been talking about using 4 Subs in a proposed Stereo configuration. The next example will show another mock configuration I have been playing with using 3 Mono Subs (I think). I believe this would result in a Mono Sub configuration because I have set the "Speakers" Tab configuration to "Route Bass to All Subs" but the part I'm a bit unsure of is the layout seen on the "Playback Format Channel Routing Tab". I've not been able to find any good explanations on how this Tab works in the documentation for Audiolense. In my example shown below I've been going on the assumption that a value of "1.00" means 100% of the signal for a given channel. So based on that my thought is that by configuring a value of ".50" means that half of the signal received by that particular Sub will come from the Left Channel and the other ".50" or Half of the signal received will come from the Right Channel resulting in a Summed Mono Sub? Also seen in the example below on the same Tab are the other two Subs which are set to a value of "1.00" each (one for Left and one for Right Channels). This would suggest that those two Subs might still be considered Stereo since the signal they receive only comes from either the Right or Left Channels exclusively. But again I am not sure?

3 Sub Configuration

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My appologies in advance for this long winded post but hopefully someone can shed some light on my questions and confirm or debunk my assumptions with the two proposed new configurations.

Thank you
 

Iansr

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Some nice gear you have there. I’m no expert on multi sub set ups but I’m pretty sure Geddes recommends mono multisubs and not having them in symmetrical locations.
 

justbob

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Some nice gear you have there. I’m no expert on multi sub set ups but I’m pretty sure Geddes recommends mono multisubs and not having them in symmetrical locations.
Thank you!

The placement of the two Subs I have now was dictated by a combination of "sub crawl" measured values, wall outlet locations and lastly what I can live with in terms of their positioning within the listening room. After re-assessing the room now that I have lived with the existing Subs for awhile I have determined that there are two remaining places in the space where I could place additional Subs. Both of those places have been found to be additional hot spots in terms of their measured "sub crawl" values using a SPL Meter.

The existing Subs are somewhat symmetrical in terms of being placed at obvious Left/Right positions in the room but one Sub is a bit more forward than the other due to a door being nearby thus it had to moved forward a bit more than I would have preferred. I got somewhat lucky in that both current locations were definite trouble spots in the room so it kinda worked out well for me that way.

The two new locations where I could place additional Subs are not as symmetrical though. I am leaning more towards adding just one additional Sub because it would be placed in between the two main speakers and I think feeding it a Summed Mono signal makes the most sense due to its location. This would then probably require me to change the other two existing Subs into Summed Mono also unless Audiolense allows for a Stereo and Summed Mono configuration but I have not been able to figure out how to do that when playing around with the Speaker setup options in Audiolense as I mock up different scenarios.

Below is a overhead view of the room and speaker locations today with the two Red X's being the two new potential locations:

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specht007

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If the question is whether more subs make sense or where you should put them you can check this out in REW:

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However In my case according to REW 4 subs were worse than 2 theortically, but in real life they were delivering a better performance:

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4 subs
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2 subs

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Your experimental sub settings seem ok to me, but you could also try a 4 driver sub (this is what I am using today).

There‘s also another option described here:

I would also consider using @Mitchco ‘s Calibration service. I just did this recently and it helped me a lot in finetuning.
 

justbob

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Onnly route to left and right speaker above. The bass offloading in the speaker tab takes care of it. You should only route LFE channel directly to sub when you have play e.g. 5.1 format.
Thank you for the clarification Bernt. Its good to know that the "Routing" config Tab is not necessary to mess with for my purposes outlined other than for the two main channels.

One last question if I may....is it possible in the configuration to set one or more Subs to a different x-over Freq than other Subs? So for example, if I have two Subs set to receive offloaded bass from the main towers at 65hz via the Speaker setup Tab using "Offload All Bass" or "Route Bass To" options am I able to set a third or fourth sub to say 30hz while the first two are still set to 65hz? Or an added bonus, maybe even the third Sub be at 30hz and a fourth to 75hz while the first two are still using 65hz?

Or do all Subs need to be set to the same x-over Freq?

Thanks
 

justbob

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If the question is whether more subs make sense or where you should put them you can check this out in REW:

However In my case according to REW 4 subs were worse than 2 theortically, but in real life they were delivering a better performance:

Your experimental sub settings seem ok to me, but you could also try a 4 driver sub (this is what I am using today).

There‘s also another option described here:

I would also consider using @Mitchco ‘s Calibration service. I just did this recently and it helped me a lot in finetuning.
Hello and thanks for your reply.

My questions were more towards the configuration required within Audiolense in order to have a 3rd or 4th Sub added to my existing setup and what that configuration looks like within the various Speaker Setup Tabs. In addition to that, I was hoping to hear more about what the "Playback Format/Channel Routing Tab" values actually mean and how they are used.

I've played around with the REW simulations that you mention but in all honesty haven't found them to be even remotely accurate for a room that doesn't fit into the most basic of dimensions. By this I mean, unless you have a standard room shaped like a box with a flat ceiling the simulation output doesn't resemble the actual measured results taken at all. To be fair, I've yet to find any simulation that takes into account a sloped ceiling, vaulted ceiling or god forbid a multi-sloped and vaulted ceiling like I have. To add to all that, my room is quiet "Open" to the Kitchen and hallway feeding the rest of the house. :blink:

I've read many of @Mitcho's great posts found around the web and learned quite a bit from them. For my own reasons I prefer to do things myself even if it takes me ripping out all the hair I have left on my head to get there. I guess I'm stubborn that way but do enjoy spending some of my free time messing with it all despite this.

My current room measurement responses aren't too horrible as is but my reasons for wanting another Sub or two are to fill in a few "Nulls" that remain which bug me to look at and see. The reality is, they probably don't even matter but....:greengrin:

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juicehifi

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When you look at bass performance it is better to look at an unfiltered response.
 

justbob

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When you look at bass performance it is better to look at an unfiltered response.
Ha...it doesn't look as pretty then :)

The previous chart was with 1/6th smoothing which if I'm not mistaken is considered close to how we humans perceive it all.

Below is the same chart zoomed in real close and ugly like. This shows from 10-200hz or so. The bottom line being the same measurement as previously posted and the top line is how the room measured before I lost the configuration I was using at the time :mad:

I haven't yet been able to get back to that better looking sweep ever since because I can't find the exact settings I was using to achieve it. Nothing in the room has changed between the two sweeps shown below. Equipment and Speaker/Sub positioning all the same.

I do wonder though if its because with the new sweep and settings (ie..The uglier one below) I do not have "10db Amplification of LFE" Checked off in the "Playback Channel & Routing Tab" of Speaker Setup? I haven't yet had a chance to try and check that box and do a new round of measurements/corrections..etc.

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juicehifi

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The 10 dB LFE amplification is independent of the measurement.

Yes it is unusual to see such differences between two measurements. I wouldn't search for the prettiest possible measurement, though. In this case I'd do more measurements and worry about consitency. The bass response should be very similar from measurement to measurement, taken from fairly the same location. Everything here looks very correctably to me. The narrow throws will not go away, but they will become even narrower and are unlikely to be audible.
 

justbob

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The 10 dB LFE amplification is independent of the measurement.

Yes it is unusual to see such differences between two measurements. I wouldn't search for the prettiest possible measurement, though. In this case I'd do more measurements and worry about consitency. The bass response should be very similar from measurement to measurement, taken from fairly the same location. Everything here looks very correctably to me. The narrow throws will not go away, but they will become even narrower and are unlikely to be audible.
Hello Bernt,

I'm not sure I follow what you mean about the 10db LFE checkbox. Are you saying that the 10db bump doesn't happen during the initial sweep/measurement within Audiolense? If that is the case does it mean the 10db bump only happens during playback once the correction/filters are generated and added to the music playback software application (ie..when playing back in Roon)?

If the 10db bump doesn't happen until playback then this may be my issue because the way I do REW measurements is by generating the correction/filters then add them to ROON's convolution. I then use a sweep file I generated within REW and play it back by adding it to ROON as a music file in my library with the AL correction applied to it. Then I take the measurement with REW while that sweep file is played back via ROON.

In looking at the two sweeps previously posted (ie..the previous better one vs the current one shown) there appears to be a good 10db unexplained difference between them. I know that I didn't have the 10db LFE bump selected within Audilense during my current measurements and very well may have had it selected during the previous better looking sweep.

Thanks again
 

juicehifi

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The 10 dB lift for the LFE does not ifluence the measurement, but it is implemented in the correction filters. So the answer to your question is yes.

The second (lowest graph) in your last chart - was that after correction? If it was, something doesn't work quite as it is supposed to there. But yes, the level difference could potentially be explained by the 10 dB LFE setting.

How did you do the control measurement with Roon? and which correction do you apply in ROON? Regular stereo?
 

justbob

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The 10 dB lift for the LFE does not ifluence the measurement, but it is implemented in the correction filters. So the answer to your question is yes.

The second (lowest graph) in your last chart - was that after correction? If it was, something doesn't work quite as it is supposed to there. But yes, the level difference could potentially be explained by the 10 dB LFE setting.

How did you do the control measurement with Roon? and which correction do you apply in ROON? Regular stereo?
Hello Bernt,

Yes the current measurement graph previously shown (the lower ugly one) was done with the AL correction filter enabled in ROON via its convolution feature. That's the one were I did not have the 10db LFE checkbox enabled within AL when taking the original sweep or when generating the final correction/filter.

The way I do the final measurement once I generate the AL correction files is that I load that filter into ROON and have it enabled. Then I select the REW sweep file that I created with that application. Its a 2M file @24/192Khz that's about 9-10sec long and goes from 10hz-24Khz. I load that file in the playback queue of ROON and set the DSP volume in ROON to my default level I always use (-20dbfs) which is the same level I use when taking the initial AL measurements. Before playing the sweep I set REW to "listen/wait" for the short sweep signal to play and it sits there waiting until I hit Play within ROON. REW then takes the measurement while that sweep is played back.

I have ROON set in 7.1 Mode. Below is the contents of the AL .cfg file (I chopped off the long name of the .wav just for this example here) associated with the correction filter I am using which represents the ugly lower measurement on the graph I posted previously.

Before using the initial generated AL correction .cfg file that goes along with the .wav file I go into the .cfg file and edit it to work with ROON. The edit involves removing the full path usualy seen before the .wav file name (ie...C:\correction files\new correction\myxxxxxx.wav). I also have to edit the very top line seen below from "192000 2 4 0" TO " 192000 2 8 0" and then I ADD four additional "Zeros" on the 3rd line seen below (ie.. 0000 TO 00000000).


192000 2 8 0
0 0
0 0 0 0 0 0 0 0
myxxxxxxxxx.wav
0
0.0
2.0
myxxxxxxxxx.wav
1
0.0
0.0
myxxxxxxxxx.wav
2
1.0
3.0
myxxxxxxxxx.wav
3
1.0
1.0
 

juicehifi

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Looks like a regular two-way stereo to me with tweeters or mains on output 2 & 3, and woofers on output 0 & 1. does that sound about right?
 

justbob

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Hey Bernt.

Below are the settings in AL. Top are the settings seen in the XO Tab of Speaker Setup and Bottom are the settings seen in the Measurements screen. The Measurement screen Output CH Mappings (Bottom) look correct in terms of how they are physically wired (with the assumption that CH 0 in Audiolense equaling CH 1 on the DAC)

Hrrrm..But the XOver CH ID's dont seem to Jive as I look at them now.

At the DAC Output Cables (its an 8ch Analog Mogami Snake Cable)

CH 1 is Left Main Tower (FL Tweeter)
CH 2 is the Right Main Tower (FR Tweeter)
CH 3 is the Left SUB (RearLeft SUB or Midbass)
CH 4 is the Right SUB (RearRight SUB or Midbass)

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juicehifi

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Yes, this looks exactly as I expected.

I recommend to sweep the woofers higher, though. It tends to give a more reliable measurement of arrival time. You could try as high as 1 kHz.
 
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